That mileage you listed is the same as their 5 liter engine is getting. The ecoboost engine does shine a bit mileage wise when towing.
Over 8 1/2 years, and 125,000 miles, my Titan has average 14.44 mpg's. About 20% of those miles are towing 5000 lbs on the highway. I keep meticulous records for income tax purposes.
04 SE, White, CC, 4x4, B.T., Pop w/capt's, Util. Bed package,Splash Guards,Floor Mats. No mods.(none planned except for inchannel vent visors and an 07 exhaust). Gas whore.